I doubt you will be able to get 2 carboys in there, but you should definitely be able to get 2 cornies. I ferment in cornies myself for that exact reason. I can fit 2 of them in my fermentation fridge.

Very cool Grandmother must have been a party
Girl. I have an old Hoff Stevens keg also. Itâ€™s all
Cut and the bung hole are all welded. I was going
To use as a second mash Tun or second boil pot.Then on the other hand I have 2 ten gallon cooler one for
Electric htl and the other for a mash Tun oh and a 5 gallon mash
Tun. TOOOOOO mean toys

I doubt any distributor would take a hoff-stevens keg. No one uses them anymore. No handles, etc. Sankey kegs are either very expensive to purchase legally or illegal. You could try a scrap metal dealer or just go to Sabco. There are better deals out there but you have to hunt around and be patient. Most people just find theirs abandoned or otherwise illegally obtain them. I don't recommend this, but it is the most common option.

It might be more useful as a fermentation vessel. drill out the bunghole on the side and build a cradle to hold it. put an airlock in the bunghole and you can ferment a tenb-gallon batch in one vessel instead of breaking it up.